Self Assembly

Balloons can be used to model molecules attached to a surface. In this case the balloons are filled with helium and have a steel ball as a weight in one end. A breeze is used to model thermal energy.

Clicking a thumbnail on this web page (http://chemistry.beloit.edu/edetc/cineplex/balloons/index.html) shows a movie of that demonstration.

Balloons as models.

Deposition of molecules on a surface.

Molecules on a surface are in constant motion.

An increase in ambient energy on the left side of the surface causes a drift in surface coverage.

A step edge is higher in energy.

When ambient energy is increased the surface-molecular attraction may no longer hold the molecules.

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